Importance

Loading Importance Indicators...

Abstract

The specification relates to a broadband multiple access protocol for bi-directional hybrid fiber/coax (HFC) networks and other shared media networks. The protocol supports downstream broadcast transmission from headend to cable modem, and also provides for allocation of bandwidth for cable modems to transmit back to the headend. The HE transmits and receives control messages in either ATM or VL format, depending upon CM capability, the determination of CM capability ascertained by the HE during the message flows interchanged between HE and CM while establishing a data link. Although the present invention is described in relation to an HFC network, it is also equally applicable to other shared media networks. The protocol supports different data access modes such as STM, ATM, and VL; within each subframe of a subframe/frame/masterframe structure. The protocol adapts to changing demands for a mix of circuit and packet mode applications and allocates upstream and downstream bandwidth in response to the a variety of bursty and isochronous traffic sources. In order to satisfy the quality of service requirements of varied applications, while maintaining high bandwidth efficiency, the protocol utilizes a subframe structure with subframe partitioning into regions; one region dedicated to STM payload transmission, a second region dedicated to ATM cell transmission, and a third region dedicated to VL payload transmissions.

Loading the Abstract Image...

First Claim